But we will see fluctuations up and down over the course of the year

This is a feature of the way the climate relates to the overall earth systems, the CO2 level drops as vegetation grows in the northern hemisphere summer, and then rises during the northern hemisphere winter, peaking in the spring, and then starting to fall off again in June. On an annual basis this fluctuation is around 6 ppm, but year on year we are averaging nearly 2ppm higher - but this varies with the economy and the weather in any year, hot years tend to be associated with a higher rise.

Below is sample data extracted from CO2Now.org which is also the source of the badge.

Year

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Average

1959

315.62

316.38

316.71

317.72

318.29

318.16

316.55

314.80

313.84

313.26

314.80

315.59

315.98

1960

316.43

316.97

317.58

319.02

320.02

319.59

318.18

315.91

314.16

313.83

315.00

316.19

316.91

2008

385.42

385.72

385.96

387.18

388.50

387.88

386.38

384.15

383.07

382.98

384.11

385.54

385.57

2009

386.92

387.41

388.77

389.46

390.18

389.43

387.74

385.91

384.77

384.38

385.99

387.27

387.35

Overall this is a large scale experiment

How much CO2 can humans add to the atmosphere without adversely affecting the climate systems that we depend on?